The vets should give you some painkiller for her. Normally people keep their buns in a small area for about a week to make sure it heals up well. And sometimes bunnies chew on the stitches and you have to get a no chew wrap? I think its called.
Anyway, I don't know much about this but you can start a thread asking about it. I'm sure you'll get lots of advice! You can also ask the vet questions. Good luck with the spay!